1. Field of the Invention
The present invention relates to an optical fiber and a method for manufacturing the optical fiber and, more particularly, to an optical fiber having internal electrodes and a method for manufacturing the optical fiber having internal electrodes.
2. Description of the Related Art
Conventional optical fibers play an important role in communication, detection, and photoelectric fields. Recently, optical fiber gyroscopes are widely used in cell phones, navigation, and flight, wherein phase modulation can be achieved through transmission of signals and optical energy by optical fibers with electrodes.
In a conventional approach of producing internal electrodes in an optical fiber, a plurality of holes is drilled in a preform made of quartz glass, and a positive electrode, a negative electrode and a fiber core made of the same material as the preform are inserted into the holes. Next, an end of the preform is heated to melt, and general optical fiber drawing is carried out at the molten end of the preform. In another approach, after drilling holes in the preform made of quartz glass, a fiber core made of the same material as the preform is inserted into one of the holes. Next, general optical fiber drawing is carried out at the molten end of the preform after heating an end of the preform to melt. Then, electrode materials for forming a positive electrode and a negative electrode are heated and poured into the remaining holes to accomplish production of the optical fiber with electrodes.
Although the above approaches can produce optical fibers with internal electrodes, if the above approaches are used in producing optical fibers including fiber cores made of a crystal material, the preform is generally heated to a temperature above 1800° C., such that the positive and negative electrodes and the crystal fiber cores melt during the optical fiber drawing procedure or even melt together in a lump, failing to provide desired integrity of the positive and negative electrodes and the crystal fiber cores. Thus, the conventional production methods can not be used to produce crystal fibers with internal electrodes and crystal fiber cores. Furthermore, the crystal fiber cores could melt thoroughly under an excessively high temperature and, thus, lose their functions. Furthermore, in production of both of conventional optical fibers and crystal fibers, drilling holes in the preforms require extremely high accuracy, adding difficulties in troublesome production procedures and reducing the efficiency of the conventional methods.
On the other hand, since the conventional production methods requiring high-temperature processing can not be used on crystal fibers, in a case that crystal is used as the element material, the volume of the crystal is limited by the size of the conventional waveguide element and, thus, can not be replaced by crystal fibers, resulting in a great obstacle in miniaturization of current products.
Thus, a need exists for a novel method suitable for manufacturing a crystal fiber with internal electrodes without the above disadvantages.